Research makes biopesticide production easier and more economically viable

Discovery by scientists from Embrapa Meio Ambiente (SP) and the Federal University of Goiás (UFG) should facilitate the production of the fungus beauveria bassiana, a species that is harmful to insect pests and is widely used in the composition of biological pesticides. Researchers have discovered a cheaper source of nitrogen from plant proteins. The supply of nitrogen is an essential part of the production of this fungus and is the most expensive nutrient in the culture medium for this microorganism.

The team replaced expensive yeast extract with plant-based protein sources and found an economical and efficient alternative for large-scale production of the fungus. This recent discovery involving the liquid fermentation process of beauveria bassiana revealed the viability of plant-based nitrogen sources in the production of blastospores of this fungus. Blastospores are cells produced by liquid fermentation by several fungi that cause diseases in insect and mite pests.

The researchers point out that the vegetable proteins to be used in the process can be obtained from byproducts from agro-industrial processes. This substitution, in addition to offering a more economical alternative for large-scale production of the fungus, is also a more sustainable solution when processing a material of low economic value and considered a byproduct by the agro-industry.

For the first author of the paper, Valesca Lima, from UFG, this discovery will drive new advances in the production of biopesticides, making it more accessible and sustainable. “The use of organic nitrogen from agro-industrial byproducts not only reduces the operational costs of producing fungi through liquid fermentation, since it reduces the dependence on expensive nitrogen substrates, but also contributes to the valorization of these compounds by converting them into sustainable biopesticides. All this without losing the desirable characteristics of the bioproduct, such as high production, virulence and tolerance to abiotic factors”, says Lima.

Superior microorganism performance

Blastospores produced in media with plant-based nitrogen sources resisted abiotic stresses and were efficient in combating pests. In addition, they survived longer after being dehydrated, depending on the nitrogen source used. Cottonseed meal, used as a protein source, was the one that presented the best results, helping to create a good nutritional balance for this fungus. “Our data show that cottonseed meal is excellent for producing blastospores that are effective against pests and resistant to abiotic stresses for several strains of beauveria bassiana”, says Gabriel Mascarin (photo above), from Embrapa.

Mass production of these fungi, using plant sources of nitrogen, also results in high productivity in a shorter fermentation time, ranging from two to three days. In addition to B. bassiana, this approach can be applied to other entomopathogenic fungi (harmful to insects), expanding the repertoire of biopesticides available on the global market based on blastospores.

According to Lima, the results show that cottonseed meal not only increased blastospore production of B. bassiana, but also improved virulence against larvae of a pest. These blastospores demonstrated greater tolerance to heat and UV-B radiation, critical factors for the efficacy of biopesticides. In bioassays, blastospores from cottonseed meal caused significant and rapid lethality and also required a smaller amount of inoculum to kill the target pest population, resulting in a lower lethal dose required for effective pest control.

The use of agro-industrial byproducts as a source of nitrogen promotes more sustainable practices by transforming waste into valuable products. These byproducts from the grain agro-industry are rich in nutrients and diverse chemical compounds, making them a viable raw material for the production of microbial agents. “The integration of knowledge involved in this study is applicable to several fungal biopesticides,” highlights Lima.

The scientist says that mass production of blastospores by submerged liquid fermentation is more advantageous compared to fermentation on solid substrate, due to its scalability, high yields in short cultivation periods and lower operating costs. This technology offers more rigorous control of fermentation parameters, resulting in a lower risk of contamination and greater production efficiency.

Future implications and market potential

The study highlights the importance of an integrated approach that combines genetics and nutrition to cultivate more robust blastospores that are effective in controlling pests. Cottonseed meal and other low-cost nitrogen sources tested were shown to be suitable for high-quality production, with greater resistance to abiotic stresses and improved storage stability.

Scientists believe these findings are key to developing new biopesticides, aligning with the principles of a green circular economy. Furthermore, the nutritional versatility of B. bassiana facilitates its colonization in different ecological niches and hosts, confirming its effectiveness as a biopesticide.

“This breakthrough is essential for the commercialization of high-quality bioproducts with a positive impact on human and environmental health, and represents a significant step forward in global mycopesticide innovation,” concludes Mascarin.

Team and publication 

The following people participated in this work: Valesca Lima, Alexandre Matugawa and Éverton Fernandes, from the Federal University of Goiás, and Gabriel Mascarin, from Embrapa Meio Ambiente. The complete work can be accessed at the link: https://journals.asm.org/doi/10.1128/spectrum.04040-23